Heart disease health centre

Introduction

A cardiac arrest is a medical emergency. When someone has a cardiac arrest, it means their heart stops beating and you can't feel a pulse. If you find someone like this, it's vital to get their heart started again as quickly as possible. You or someone with you will need to dial 999 to get medical help. If you have training in cardiopulmonary resuscitation (CPR), you may also be able to increase someone's chances of surviving a cardiac arrest.

We've brought together the best research about cardiac arrest and weighed up the evidence about how to treat it.

When someone has a cardiac arrest, their heart stops pumping. This means blood doesn't flow around their body and oxygen doesn't reach their brain and other organs. If a person's heart stops pumping for more than a few minutes, they are unlikely to recover.

To understand what happens during a cardiac arrest, it helps to know a little bit about your heart. To read more, see How your heart works.

Before a person has a cardiac arrest, their heart beats abnormally. Two things can happen.^[1]

• Their heart beats fast (150 to 200 beats a minute). The beats start in the lower chambers (ventricles) of the heart, instead of the upper chambers. Doctors call this pulseless ventricular tachycardia.

• Their heart beats very fast (more than 300 beats a minute) and very irregularly. The beats again start in the ventricles, instead of the upper chambers of the heart. Doctors call this ventricular fibrillation.

If a person's heart beats like this, blood isn't pumped to their lungs, the rest of their body, and back to their heart. This is a cardiac arrest. It's a dangerous medical emergency that needs urgent treatment.

A cardiac arrest isn't the same thing as a heart attack. Heart attacks happen when a blood clot blocks the flow of blood to the heart. However, a heart attack can lead to cardiac arrest.

You are more likely to have a cardiac arrest if:^[1]

• You have heart disease

• You've had a heart attack

• You have heart failure

• You're middle-aged or older

• You're a man.

Glossary

heart disease

You get heart disease when your heart isn't able to pump blood as well as it should. This can happen for a variety of reasons.

heart failure

When the heart loses its ability to push enough blood through the blood vessels, it is called heart failure.

For more terms related to Cardiac arrest

Citations